1. Field
One or more exemplary embodiments relate to a foldable display device.
2. Description of the Related Art
Typical foldable display devices are portable and have a relatively large-sized screen for the display device size. Foldable display devices are applied not only to mobile devices such as mobile phones, portable multimedia players (“PMPs”), navigation systems, ultra mobile personal computers (“UMPCs”), electronic books, electronic newspapers, etc. but also to televisions and monitors.
However, one of the problems of foldable display devices is the reliability of folding portions thereof, e.g., the sections of the display device which are subjected to folding stresses. To address this problem, a flexible substrate formed of plastic or metal foil is typically used as a substrate of the foldable display devices. However, due to the physical limits of flexible substrates and the need to protect thin film transistors (“TFT”), it is difficult to reduce the radius of curvature in the folding portions of the foldable display devices. Accordingly, since a large radius of curvature is to be provided in the folding portions of foldable display devices of the related art, the typical foldable display devices may only have correspondingly large thicknesses.
In addition, in order to realize a driving unit including a TFT on a substrate formed of a plastic material or a metal foil, an organic TFT or a low temperature process Si TFT is typically used due to the process of manufacturing foldable display devices. However, organic TFTs and low temperature process Si TFTs have low yields compared to amorphous Si TFTs.